You are using a component that writes log messages with Commons Logging, and you need to configure the underlying logging implementation.
If the system property org.apache.commons.logging.Log
is not set,
Commons Logging will use Apache Log4J if it is available in the
classpath. To explicitly configure Commons Logging to use Log4J, set the
org.apache.commons.logging.Log
property to org.apache.commons.logging.impl.Log4JLogger
with the following statement:
System.setProperty( "org.apache.commons.logging.Log", "org.apache.commons.logging.impl.Log4JLogger" );
If the system property org.apache.commons.logging.Log
is not set and
Apache Log4J is not available on the classpath, Commons Logging will
then use the built-in JDK 1.4 logging framework. To explicitly configure
Commons Logging to use the JDK 1.4 logging framework, set the org.apache.commons.logging.Log
property to
org.apache.commons.logging.impl.Jdk14Logger
.
If neither Apache Log4J nor the JDK 1.4 logging framework is
available on the classpath and the org.apache.commons.logging.Log
system
property is not set, Commons Logging uses a basic logging implementation
named SimpleLog
. To explicitly
configure Commons Logging to use SimpleLog
, set the org.apache.commons.logging.Log
property to
org.apache.commons.logging.impl.SimpleLog
.
To summarize, Commons Logging performs the following steps when choosing an underlying logging implementation:
Checks the org.apache.commons.logging.Log
system
property. If this property is set, use the class specified in this
property.
Checks for the presence of Log4J in the classpath. If Log4J is
present, use a Log4JLogger
instance.
Checks for the presence of the JDK 1.4 logging framework. If
JDK 1.4 is present, use a JDK14Logger
instance.
If neither Log4J nor JDK 1.4 is available, use SimpleLog
.
For more information about the configuration of Apache Log4J, see Recipe 7.13 and Recipe 7.14. For more information about the configuration of the JDK 1.4 logging framework, see Sun's documentation of this framework at http://java.sun.com/j2se/1.4.2/docs/guide/util/logging/.
SimpleLog
is a very simple
logger that can be used when an application does not need a complex
logging framework. For more information about configuring SimpleLog
via system properties, read the
Commons Logging JavaDoc at
http://commons.apache.org/logging/api/index.html.